In the past, rotary drill bits have incorporated cutting elements employing superabrasive materials. Within the industry there has been widespread use of synthetic diamond cutters using polycrystalline diamond compacts, otherwise termed “PDC” cutters. Such PDC cutters may be self supported, otherwise a monolithic object made of the desired material, or incorporate a polycrystalline diamond layer or “table” on a substrate made of a hard metal material suitable for supporting the diamond layer.
However, PDC cutter designs continue to face obstacles. For example, mechanical strains are commonplace given the significant loading on the cutters, and as such, delamination and fracture of the cutters, particularly of the diamond table, can occur given the extreme loading and temperatures generated during drilling operations. Furthermore, failure of the cutters due to temperature concerns can go beyond the existence of simply encountering high temperatures. In addition, the effects of heating and cooling on the cutters and the resultant failure of the cutters is also due to differences in thermal expansion coefficient and thermal conductivity of materials within the cutter.
Various different configurations of cutters have been used to mitigate the effects of mechanical strain and temperature-induced wear characteristics. However, significant shortcomings are still exhibited by conventional cutters.